CRAM Hardware Information
CRAM is designed for use in the field with a dedicated tablet computer. The CRAM team has tested two tablets for use with the CRAM software.
Hewlett-Packard tr3000 [now available as the Itronix Duo-Touch]
Cost: about $2000 and up, depending on configuration
Screen size: 8.5 inch
Weight: 3 lbs 14 oz
Battery life: standard battery: ~2 hrs
Pros
- Ruggedized—all ports have rubber covers; rubber padding on edges
- Bigger screen
- Stylus has tether, preventing loss
Cons
- Can get uncomfortably hot
- Weight can get tiresome
- Screen readbility outdoors is fair [In May 2007 this tablet was offered with a new sunlight-readable display. The CRAM team has not tested the new display, but expects a significant improvement in outdoor readability.]
Samsung Q1
Cost: about $1100
Screen size: 7 inch
Weight: 1 lbs 11 oz
Battery life: standard battery: ~2 hrs. External battery pack (Samsung PowerBank): 9 hrs (claimed)
Pros
- Light & compact
- Stylus has better feel (a somewhat subjective point)
- Lots of custom accessories available (case, keyboard, external DVD drive, larger battery packs)
- Has built in stand (not unlike a picture frame) for desk use
Cons
- Not ruggedized. No special protection against dirt & water
- Easy to lose small stylus, no simple way to attach tether
- Optional folding case that holds optional keyboard is awkward to use in the field
- Screen readbility outdoors is fair
Other options
There are many other tablet computers (rugged and conventional) available, including units with screens designed for viewing in direct sunlight. Time and budget contraints prevented the CRAM team from making a comprehensive evaulation of the possibilities. As we gather more information from our own testing and from other CRAM users, we'll post that information here. Please send information on your experiences to cram
cramwetlands.org.
Other computers that appear to be good candidates for CRAM fieldwork include:
Battery life
The CRAM team recommends a solution that provides at least 6 hours continuous run time, which should support two CRAM assessments. Neither tablet we evaluated approached this battery life in its standard configuration. The recommended solution is an external battery pack. With a suitable cord length, the external battery pack can be carried in a daypack while collecting CRAM data.
The HP tr3000 with power supplied by external battery pack. Note power cord leading to external battery in daypack.
Samsung makes an external battery pack for the Q1 (the PowerBank) that provides a claimed 9 hours of battery life.
With the HP tr3000, the CRAM team has used a universal external battery pack (available from Battery Geek). Check their recommendations for your particular computer. For the battery pack used with the tr3000, a 6-foot power extension cord (Radio Shack part no. 273-1641) provides the length needed to carry the pack in a daypack. (Unfortunately, Radio Shack appears to have discontinued this particular item. With access to soldering skills, you can create esssentially the same item using Radio Shack parts 273-1742 and 273-1740.)
HP tr3000 tablet with universal external battery pack and 6-foot power extension cord.
Charging batteries in the field
For charging batteries without access to an electrical outlet, auto power inverters are available. These plug into the cigarette lighter of your vehicle and provide a standard 120V AC outlet for recharging. The CRAM team has purchased the Xantrex Pocket Inverter 175 ($40) to charge the HP tablet and external battery pack while on the road. This unit is reasonably compact and comes with a zippered soft case. In addition to a 120V AC 3-prong outlet, the unit has a USB port to charge USB-powered devices. Care should be taken when using this device to not deplete the auto battery such that the vehicle fails to start. The safest approach is to charge only when the engine is running, such as when traveling betweeen CRAM areas.
Xantrex PocketInverter 175. Note quarter for scale.